| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
| ||||||||||||||
| ||||||||||||||
|
|
|
|
||||||||||||
|
||||||||||||||
Department of Anesthesiology, Bispebjerg University Hospital, Copenhagen, Denmark
Address correspondence and reprint requests to Tom Pedersen, MD, PhD, Department of Anesthesiology R, Bispebjerg University Hospital, 2400 Copenhagen NV, Denmark. Address e-mail to doctp{at}yahoo.com
 |
Abstract |
|---|
 Top Abstract IntroductionEBM in Clinical PracticeConclusionReferences |
|---|
IMPLICATIONS: This article illustrates the basic principles of evidence-based medicine and the work within the Cochrane Collaboration and the Cochrane Anesthesia Review Group. It describes how important randomized controlled trials and systematic reviews are in providing the best evidence to answer clinically relevant questions.
|
Introduction |
|---|
|
TopAbstractIntroductionEBM in Clinical PracticeConclusionReferences |
|---|
This article will illustrate the basic principles of evidence-based medicine and the work within the Cochrane Collaboration and the Cochrane Anesthesia Review Group. It describes how important randomized controlled trials and systematic reviews are in providing the best evidence to answer clinically relevant questions.
|
EBM in Clinical Practice |
|---|
|
TopAbstractIntroductionEBM in Clinical PracticeConclusionReferences |
|---|
Ask a Clinical Question You Can Answer
To find an answer to your clinical question, it will need to be clear and well focused. That is: what is the question about? How could you describe a group of patients similar to this particular patient (e.g., an overweight pregnant woman or an elderly person with coronary heart disease)? Which treatment or maneuver are you considering for the patient? (e.g., type of anesthesia, route for central venous catheterization or antibiotic in the intensive care unit). What is the desired (or undesired) outcome for the patient? (reduced postoperative nausea and vomiting, reduced morbidity or mortality, reduced costs).
A good question will cover these three areas of subject, intervention, and outcome, each of equal importance. Failure to frame the question properly will make it hard to find useful and applicable answers. For example, contrast "Is propofol a better induction drug than thiopental?" with "Does propofol lead to fewer unexpected overnight admissions than thiopental after adult day case laparoscopic sterilization?"
Search for Evidence
Information technology has undoubtedly made it easier to search the medical literature, and most institutions provide computers that allow electronic searching. MEDLINE is well known to most doctors, and a subject can be searched by free text and index terms. The Cochrane Library (see full description later in text), EmBase, and Biosis, as well as other databases, can be sought.
Critical Appraisal of the Evidence
Critical appraisal is the process whereby we attempt to answer two main questions about the material we have retrieved in our search. These are 1) are the results important (useful for you as a clinician)? If a study concludes that a diagnostic test is inaccurate or that a treatment has only a negligible effect on patient outcome, there is no need to go through the text to appraise the validity of the study. If however, results are judged to be important, go back and ask 2) are the results valid (close to the truth)? Several questions have to be posed: e.g., was the design of the study sensible? What was the intervention studied and what was it compared with? If the trial was about treatment or prevention, was the assignment of patients randomized, and was the allocation procedure concealed? Were all the patients who entered the trial accounted for at its conclusion, and were they analyzed in the groups to which they were randomized? What outcome was measured and how? Was the outcome assessor blinded? Was a surrogate end point used? Were the statistics used correctly? Finally, were the conclusions that were drawn by the authors supported by the results? Together, these questions help to judge the clinical applicability of the study results.
Clinical Applicability of Evidence-Based Findings
After critical appraisal, some questions remain: how can you integrate this evidence with your own clinical expertise and decide whether and how to incorporate it into the care of your patient? Do these results apply to your patient? Is your patient so different from those in the trial that the results cannot help you? (Can the results be generalized?) Does the intervention match your patients’ (and your) preferences? It is then a clinical decision to estimate the potential benefit of the intervention for the individual patient.
Evaluation
After going through the process of applying EBM in patient care, it is necessary to evaluate the process. How well did we succeed in using EBM? Did we ask the right questions? Did we find useful answers? Will we actually use the findings in clinical practice? Is there anything we can do better?
What Is the Cochrane Collaboration?
The Collaboration is named after the British epidemiologist Archie Cochrane, who wrote: "It is surely a great criticism of our profession that we have not organized a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomized controlled trials" (6). His criticism is still relevant in that people wanting to make well informed decisions about health care are often confronted with hundreds of thousands of potentially relevant research reports. No one can be expected to sift through these mountains of evidence to discover which forms of health care are more likely to do good than harm.
The Cochrane Collaboration is a worldwide organization. It is composed of 50 collaborative review groups (Table 1), 10 methods groups, 14 Cochrane Centers, and the Cochrane Collaboration steering group. Collaborative review groups are composed of persons from around the world who share an interest in developing and maintaining systematic reviews relevant to a particular health area. Groups are coordinated by an editorial team, who edit and assemble completed reviews into modules for inclusion in the Cochrane Library. The Cochrane Collaboration Steering Group (CCSG) is elected to develop policies and strategies for the Collaboration. It has several subgroups responsible for specific tasks. The CCSG is supported by the Collaboration Secretariat. Methods groups are composed of individuals with an interest and expertise in the science of systematic reviews. They provide advice and support to the Collaboration in the development of the methods of systematic reviews. Each review group is supported by a center. For example, the Anesthesia Group is based in Copenhagen, and its supporting center (the Nordic Cochrane Center) is also based in Copenhagen. The work of Collaborative Review Groups, Methods Groups, Fields/Networks, and the Consumer Network is facilitated in a variety of ways by the work of more than a dozen Cochrane Centers around the world. They share responsibility for helping to coordinate and support members of the Collaboration in areas such as training, and they promote the objectives of the Collaboration at the national level.
|
|
CRGs
The main work of the Cochrane Collaboration is performed by the CRGs. These are responsible for the preparation and maintenance of Cochrane reviews. A CRG consists of individuals from around the world who share an interest in a particular health topic—in our case, anesthesiology. CRGs are coordinated by an editorial team, comprising a coordinating editor, a number of other editors, and the group coordinator. Other members of the CRG include reviewers (who write and update the systematic reviews), peer referees (individuals not involved with systematic review who offer editorial suggestions before publication), hand-searchers (who search for randomized controlled trials in journals), consumers (people using the prevention or health services), and other interested parties. The primary task of a CRG is to conduct and regularly update systematic reviews of prevention and health care issues within the scope of its group. Each CRG creates a specialized register of methodologically sound controlled studies relevant to their group, of both published and unpublished studies in all languages, avoiding publication bias (which means that the journal appears to favor trials with positive results) (7).
The Cochrane Anesthesia Review Group
The idea of forming the Cochrane Anesthesia Review Group arose in 1997. The Cochrane Anesthesia Review Group (CARG) was established in February 2000. The editorial office is based in Copenhagen, Denmark, and the editorial team consists of people from around the world.1 The main goal of the CARG is to conduct systematic reviews of randomized controlled trials and other controlled clinical trials of interventions. These reviews evaluate outcomes in anesthesia, intensive care, acute pain treatment, prehospital medicine, resuscitation, and emergency medicine.
How to Perform a Systematic Review in Anesthesia?
A review is initially registered with a Cochrane Review Group and Cochrane Title base as a title. That title will become a protocol, which prospectively sets out what is being tested, why, and how it will be done. The complete systematic review adheres to the protocol to maintain uniformity and minimize bias. Systematic reviews performed by the CARG are reviews of studies in which evidence has been systematically searched for, studied, assessed, and summarized according to predetermined criteria.
Titles
To register a title with the CARG, a reviewer submits a registration form (available on the CARG Website, http://www.carg.dk, or on request from the editorial office). The registration form should include contact details for the reviewers, a preliminary title, and a synopsis describing the background, participants, interventions, outcomes, and key words. After the title has been approved by the coordinating editors and the Review Group coordinator has excluded any potential duplication of work or conflicts of interest with other Cochrane groups, the title is registered. The reviewer is then sent guidelines for writing a systematic review ("Tips for Reviewers," available at http://www.cochrane.org/cochrane/hbook.htm), advised to read the Cochrane Handbook and glossary, and sent details of Cochrane training workshops.
Protocols and Reviews
Protocols and reviews are prepared by using the Cochrane Collaboration’s Review Manager software RevMan (which is available on CD-ROM from the editorial office or can be downloaded from http://www.cochrane.org/cochrane/revman.htm). Reviewers who do not have the computer capability to access RevMan should contact the editorial office. The Review Group coordinator acknowledges receipt of the protocol in the editorial office and forwards the protocol, along with guidelines for editing (see http://www.carg.dk: "Tips for Editors/Peer Referees"), to the assigned CARG editor and two peer referees. The editor and peer referees evaluate and comment on the review title, background, objectives, selection criteria, search strategy, methodology, and language of the protocol. The protocol and later the systematic review (the principal output of the Collaboration) will be published electronically in successive issues of The Cochrane Library’s Database of Systematic Reviews. Current reviews and protocols being prepared by members of the CARG are listed in Table 3.
|
What Is a Systematic Review?
A systematic review includes an explicit and detailed description of how it was conducted so that any interested reader should be able to replicate it. The systematic review incorporates strategies to minimize bias and to maximize precision. The systematic review includes a clear research question, criteria for inclusion or exclusion of primary studies, the process used to identify primary studies, the methods used to assess the methodological quality of the selected studies, and the methods used to extract and summarize the results of primary trials on which the conclusions are based (8).
Systematic reviews are evaluated in terms of the following questions: does the review focus on the clinical problem in question? Is the search strategy described in detail, and were all potentially important sources searched? Was the methodological quality assessed and the trials weighted accordingly? How sensitive are the results to the way the review was done? Have the numerical results been interpreted with common sense and due regard to the broader aspect of the problem? The methods for critically appraising systematic reviews in anesthesia have been described recently (4,9).
Categorizing Evidence
Summarized evidence can be categorized according to study design. It should reflect susceptibility to bias. A comprehensive plan for estimating the strength of clinical recommendations can be found on the home page of the Center of Evidence Based Medicine (Oxford) http://cebm.jr2.ox.ac.uk. An adaptation (10) of the North of England Evidence Based Guidelines Development Project (11) (Table 4) describes the categories of quality and strength of evidence in descending order of importance. Clinical questions should be answered by using the best evidence available. If, for example, a question on the effect of an intervention could be answered by Category I evidence, then studies of weaker design (controlled studies without randomization) should not be reviewed. Recommendations are based on consideration of the following: the strength of evidence, the applicability of the evidence to the population of interest, economic considerations, values of the guideline developers and society, and guideline developers’ awareness of practical issues.
|
How can it be determined whether the results of a randomized controlled trial are useful? By looking for information on how the trial was executed, one could judge how well it was executed and whether its results could be used. In a recent publication we stressed that to judge the execution of a trial, one should focus on size, methods, statistics, outcomes, and bias (4).
Other Activities of the CARG
Specialized Register (SR-ANAESTH)
The CARG maintains a register of more than 25,000 randomized controlled trials and clinical controlled trials related to anesthesia, perioperative medicine, intensive care medicine, prehospital medicine, resuscitation, and emergency medicine. The register is maintained with ProCite software, and searches for trials are executed quarterly. Trials included in the register are tagged SR-ANAESTH, and the tag term may be searched in the Cochrane Library. Access to the register is available to reviewers and other members of the CARG.
Hand-Searching
Members of the CARG are involved in searching anesthesia journals by hand to identify randomized controlled trials and clinical controlled trials for inclusion in systematic reviews, the Specialized Register, the Cochrane Library’s database, and the National Library of Medicine. The CARG is currently hand-searching the following journals: Anesthesia & Analgesia, Anesthesiology, Journal of Clinical Anesthesia, Acta Anaesthesiologica Scandinavica, Annales Francaises d’Anesthesie et de Reanimation, Anesthesia and Reanimatology, Canadian Journal of Anaesthesia, Czecko-Slovak Journal of Anesthesiologie, Journal of Cardiothoracic and Vascular Anesthesia, European Journal of Anaesthesiology, Regional Anesthesia, Intensive Care Medicine, American Journal of Respiratory and Critical Care, and British Medical Journal.
Consumer Representation
One of the goals of the Cochrane Collaboration is to make Cochrane evidence accessible to consumers through the Cochrane Library. The CARG is liaising with other review consumer groups to set up good communications and learn how to successfully involve public laypeople who have an interest in or have been subjected to anesthetic care within our group. At present, the CARG has only a few consumers, but we are in the process of collaborating with other consumer groups. More information on this subject is given in the Cochrane Consumers Network’s Website (http://www.cochraneconsumer.com).
|
Conclusion |
|---|
|
TopAbstractIntroductionEBM in Clinical PracticeConclusionReferences |
|---|
To overcome these barriers, a collaborative link has been developed between the CARG and Anesthesia & Analgesia. The intention is to disseminate evidence on interventions in anesthesiology currently found in the Cochrane Library to a wider readership. Feedback from readers of Anesthesia & Analgesia will help develop CARG’s future activities.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
|
References |
|---|
|
TopAbstractIntroductionEBM in Clinical PracticeConclusionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  L.-L. Bo, J.-B. Li, and X.-M. Deng The Assessment of Publication Quality Anesth. Analg., May 1, 2008; 106(5): 1589 - 1590. [Full Text] [PDF]
|
|
|
|
|
|
T. T. Horlocker and D. R. Brown Evidence-Based Medicine: Haute Couture or the Emperor's New Clothes? Anesth. Analg., June 1, 2005; 100(6): 1807 - 1810. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
